关于rhcs拔掉网线不切换的问题~

关于rhcs报错：
   数据库A：主机名：ehrdb1
            BMC:192.168.133.70
            eth0:192.168.133.60
            eth1:10.0.133.60
            
   数据库B：主机名：ehrdb2
            BMC:192.168.133.71
            eth0:192.168.133.61
            eth1:10.0.133.61

   虚拟IP： 10.0.133.69


版本是redhat 5.0 updata 2 ,安装的rhcs包有：cman, rgmanager

现在的状况是：
        停掉cman,rgmanager服务或者重启当前服务的主机，能自动切换到另一台机器
        
       但拔掉网线，服务就down在那，不能切换

      tail -f /var/log/messages 内容：

       Aug 11 11:01:45 ehrdb2 fenced[5028]: fencing node "ehrdb1"
Aug 11 11:01:45 ehrdb2 fenced[5028]: agent "fence_ipmilan" reports: ipmilan: ipmitool not found! failed: Failed to initialize
Aug 11 11:01:45 ehrdb2 fenced[5028]: fence "ehrdb1" failed
Aug 11 11:01:50 ehrdb2 fenced[5028]: fencing node "ehrdb1"
Aug 11 11:01:50 ehrdb2 fenced[5028]: agent "fence_ipmilan" reports: ipmilan: ipmitool not found! failed: Failed to initialize
Aug 11 11:01:50 ehrdb2 fenced[5028]: fence "ehrdb1" failed
Aug 11 11:01:55 ehrdb2 fenced[5028]: fencing node "ehrdb1"
Aug 11 11:01:55 ehrdb2 fenced[5028]: agent "fence_ipmilan" reports: ipmilan: ipmitool not found! failed: Failed to initialize
Aug 11 11:01:55 ehrdb2 fenced[5028]: fence "ehrdb1" failed

好象配置的fence设备有问题，没有起到通讯的功能

好象说redhat rhcs不支持拔网线